Post-weaning diarrhoea (PWD) is a significant enteric disease causing considerable economic losses for the pig industry. There are multiple factors for why pigs develop diarrhea post-weaning and require treatment with antibiotics. The condition ‘dysbiosis’ can be considered as an ecosystem where bacteria no longer live together in mutual harmony. With regard to development of PWD, we therefore consider this as a process in a simplistic manner, i.e., dysbiosis appears when the commensal no longer control the potential pathogenic bacteria. When the pathogenic bacteria colonize and adhere to the epithelium of the gut, they may induce diarrhea. There are a number of factors by which the gut function can be improved, and prevention of dysbiosis exert a major role herein. The objective is to provide an overview of factors, which may enhance gut function both in terms of a balanced or eubiotic ecosystem, and with regard to the epithelial barrier function.